Rift valley fever: EFSA looks at the risk of introduction and spread in Mediterranean countries neighbouring the EU

News Story
26 April 2013

The introduction of the Rift Valley fever into countries in North Africa and Middle East that border the Mediterranean Sea is most likely to occur through the uncontrolled movements of infected animals from Eastern Africa and the Arabian peninsula. This is one of the findings of a scientific opinion by EFSA’s Panel on Animal Health and Welfare (AHAW)

Rift Valley fever is a highly contagious disease that affects animals and humans, potentially leading to death. It is transmitted through mosquitoes and contact with blood or tissues of infected animals. With important implications for animal and human health, Rift Valley fever also impacts on people’s livelihood, the trade of animals and food security.

Based on the available evidence in scientific literature and outbreak reports, the AHAW Panel concluded that in the last 10 years Rift Valley fever has not spread to new countries. The Panel noted, however, that the disease has moved north within Mauritania to a desert area.

To gather information on the risk of the introduction of the Rift Valley fever virus, EFSA organised workshops with experts from the relevant Mediterranean countries and affected areas.

Looking at the geographical distribution of the mosquitoes that transmit this virus, the AHAW Panel found that the southern Mediterranean region provides favourable climatic (rain and temperature) and environmental conditions for the presence of the disease vectors, especially in summer and autumn.

In case of an outbreak, the disease could be introduced into countries of North Africa and the Middle East by infected animals moving north from East Africa or through the Arabian Peninsula. Other less likely pathways are animal movements from Central and West Africa. The Panel developed a model to assess and quantify the risk of entry of the Rift Valley fever virus in North Africa and the Middle East in case of an outbreak. Experts found it less likely that the Rift Valley fever virus would be introduced through the movement of mosquitoes than by infected animals.

The opinion also highlighted that were a Rift Valley fever outbreak to occur in countries in North Africa and Middle East, the disease would potentially spread along the coastal areas and the Nile Delta, due to the density of livestock and presence in this area of mosquitoes that can transmit the virus.

To protect Europe and the neighbouring Mediterranean countries against the possible introduction and spread of Rift Valley fever, the AHAW Panel made several recommendations. Effective surveillance, monitoring and reporting tools need to be developed to better detect changes in the occurrence of the disease in animals. Further investigations are required to map seasonal variations in the presence of mosquitoes and better understand the effectiveness of these vectors in transmitting the disease. Efforts should also be made to monitor the possible movement of animals into North Africa and Middle East.

Rift Valley fever is generally found in eastern and western Africa, but the virus also exists in southern Africa and Madagascar and along the Nile Valley. In 2000, a Rift Valley fever outbreak was reported in Saudi Arabia and in Yemen.

Countries considered in this scientific opinion are Morocco, Algeria, Tunisia, Libya, Jordan, Israel, Palestinian Territories, Lebanon and Syria. Egypt and Mauritania were excluded as the virus has already been introduced into these countries.

Rift Valley fever is a notifiable disease, according to Council Directive 82/894/EEC on the notification of animal diseases within the Community. The measures to prevent introduction and control of this disease are laid down in Council Directive 92/119.